As is common knowledge, palletised loads are normally covered with a stabilising covering that immobilises them on the pallet so they can then be transported without risk of falling or tipping over.
To make such a stabilising covering the usual way is to tightly wrap the sides of the load and pallet with a plastic covering film that is unwound from a reel of film.
Either automatic or semi automatic systems are normally used for such wrapping.
One very widely used wrapping system uses a machine to move a wrapping head equipped with a reel of covering film.
The moving machine is normally composed of a jointed robot arm that, to wind the covering film around the load to wrap, operates the wrapping head with a lifting and rotating motion around the load to wrap which substantially stays still.
Alternatively, the moving machine works by moving the wrapping head vertically, simultaneously winding the covering film around the palletised load that turns on a rotating platform.
It is also common practice to equip traditional type systems with an automatic wrapping head change unit that deposits the head in a store when the reel of covering film is finished and collects a new head ready to use.
When parking them in the store, the wrapping heads are usually placed on an external frame fitted with pins on which the wrapping head is hung waiting to be used.
For the moving machine to collect them, the wrapping heads are fitted with special coupling means that consist of a circular plate with radial hollows that can be engaged by a mobile wedge system mounted on the robot arm and operated by one or more pneumatic cylinders, also mounted on the robot arm. Once the wrapping head is associated to the robot arm, it is connected to an electrical joint and to a pneumatic feeding joint that lets it work in the palletised load wrapping phase.
These traditional wrapping systems do have a few drawbacks involving the automatic change unit which they are equipped with.
As a matter of fact the use of the mobile wedge system significantly complicates both the structure and the functionality of the moving machines.
In fact, the movability of the wedges must be inconveniently guaranteed by means of a complex electronic system that manages and controls operation of the pneumatic cylinders and of the compressed air unit that feeds them.
Neither must we neglect the fact that the automatic change unit, as it is made, is rather cumbersome and costly.